1. Field of the Invention
The present invention relates to a drive force output apparatus and a vehicle having the same.
2. Description of Related Art
Lately, there is a growing market demand for hybrid vehicles (hybrid automobiles) because of the low fuel consumption, the low exhaust emissions and the like of the hybrid vehicles. For instance, as recited in Japanese Unexamined Patent Publication JP H07-135701A, a known hybrid vehicle has an internal combustion engine and two motor generators (hereinafter, the term of “motor generator” will be abbreviated as MG) A drive force of the internal combustion engine is split into two lines through a planetary gear mechanism. An output of one of the two lines is used to drive a drive axle of the vehicle and thereby to drive wheels of the vehicle. An output of the other one of the two lines is used to drive the first MG and thereby to generate electric power. The electric power generated by the first MG and/or the electric power of a battery may be used to drive the second MG, and the drive force of the second MG may be used to drive the wheels. In this way, the internal combustion engine may be driven in an efficient torque range, and at the same time, a change in the rotational speed is enabled.
However, when the system (the system, which splits the drive force through the one planetary gear mechanism) of Japanese Unexamined Patent Publication JP H07-135701A is applied to a vehicle having the internal combustion engine of a large displacement, the drive forces, which are handled by the two MGs, are increased. Therefore, the sizes of the electric components, such as the MGs and inverters, are increased to cause a difficulty in installation of the system on the vehicle. Furthermore, the electric loss is increased, and thereby the fuel consumption is deteriorated by the amount, which corresponds to the electric loss.